Tomographic medical imaging devices or scanners such as computed tomography (CT) and magnetic resonance (MR) imaging devices are increasingly used for visualizing dynamic processes. In particular, the recent advent of Volumetric Computed Tomography (VCT) could have as strong an impact on medical imaging as that which resulted from the development of standard CT in the 1970's. Specifically, VCT relies on X-rays being directed through an object to be imaged, and large planar detectors for acquiring image data at a plurality of views. VCT utilizes mathematical algorithms to process the acquired image data to create 3-D images of the human body and its systems. These images have the potential to aid in the detection and diagnosis of disease. Accordingly, VCT also has the potential to be used in the development of new treatments and procedures. VCT is also capable of dynamic imaging, such as capturing a 3-D video of a beating heart or the perfusion of organs. Similar methods have been developed for volumetric MR, Ultrasound, and other tomographic imaging modalities.
However, before a tomographic imaging device can be accurately and safely used in the treatment of patients, it is important to define its boundaries and limitations. The temporal resolution of an imaging device indicates the fastest movements that the imaging device can resolve and faithfully reproduce. For example, if the heart of a small animal is beating extremely fast, such as 200 or 300 beats per minute, then an image of the heart produced by a typical imaging device will be blurred if the temporal resolution of the device cannot sufficiently capture this motion. Thus, the higher the temporal resolution of an imaging device, the more capable it is of producing quality images of fast moving structures inside its imaging volume. However, while methods exist for defining and measuring spatial resolution in terms of a modulation transfer function, there is no standard method for measuring temporal resolution. Prior art methods for measuring the temporal resolution of a tomographic imaging device are limited to using indirect metrics such as rotation time or the image acquisition time. In addition, a single numerical value has been used to describe the temporal resolution. Because the temporal response of an imaging device declines as faster and faster changes in the object space are imaged, the concept of progressive degradation of performance has not previously been formalized.
Therefore, it would be desirable to have a system and method for accurately determining the temporal resolution of an imaging device.